We're going to give it a whirl with Roti-feast and frozen rotifers. I'm not expecting any survival, but it will be fun to try. Wish us luck!
Kass, mandarins (Synchiropus splendidus) were first raised a long time ago. I think the biggest hindrance to their commercial success was that at about a year of age, the fish was very, very small (1cm if I recall correctly). It takes quite a while to grow them out, but I don't remember the process being much different from clowns.
Peppermint shrimp have been raised, as have Sexy shrimp, fire shrimp, cleaners, and a couple of other species of "Peppermint" (not L. wurdemanni). Not to mention most of the shrimp we eat is farm-raised. Cleaners seem to be the toughest nut to crack, as they apparently have an impossibly long larval period (90-100 days) and seem to hit a roadblock molting past Z7-Z8 a lot of the time. They continue to molt but fail to develop. There are lots of people currently working on them.